Spherical error, or overall power of lens is the basic part of your prescription. A (+) means you have trouble seeing near, and a (-) means you have trouble seeing things faraway.

CYL (Cylinder) & Axis

A cylinder value indicates astigmatisms or perpetually blurry vision. Axis—measured between 1 and 180°— tell us the orientation of the astigmatism

ADD (Addition)

This number is sometimes written NV for near vision and is used for multifocal lenses and readers

PD (Pupillary Distance)

It's just what sounds like—the distance in millimeters (mm) between your pupils. An average PD measurement is 63 mm, but varies by person. If it's not on the prescription, you can measure it yourself by printing our downloadable PD ruler.

PRISM

We can process prism prescriptions to correct eye orientation

Vertical Prism is used to help correct vertical eye misalignments and is prescribed in opposite directions for both eyes

Horizontal Prism is used to help correct lateral eye misalignments and is always prescribed in the same direction for both eyes